Selectable contact transmitter means for sensitive instruments



1 J. o. KIRWAN 4 I 2,452,764

. SELECTABLE CONTACT TRANSMITTER MEANS FOR SENSITIVE INSTRUMENTS Filed Feb. 19, 1947 INVENTOR fa/m a Kira/ax BY ATTORNEY Patentecl Nov. 2, 1948 UNITED STATES PATENT Qi FlCE.

SELECTABLE CONTACT TRANSMITTER MEANS FOR SENSITIVE INSTRUBIENTS John 0. Kirwan, Bloomfield, N. J., assignor to Wallace & Tiernan Products, Inc., Beileville, N. J., a corporation of New Jersey Application February 19, 1947, Serial No. 729,564

9 Claims. 1

This invention relates to contacting means adapted for electrical transmission of the position of an instrument or the like, and in an important specific aspect, relates to depressor-actuated, selectable-contact transmitters for delicately responsive instruments such as provide a high sensitivity and such as are actuated by small amounts of energy insufficient to provide substantial force in the translating operation.

By way of example, one prior device for accomplishing such purpose has involved a sensitive instrument of the galvanorneter type having a pointer or needle in the form of a thin rod adapted to sweep across a scale in the form of an arc of a circle. Around the periphery of the scale the device includes a row of mutually insulated teeth, fashioned of sheet metal and arranged as if out from a sheet lying in a cylinder about the axis of movement of the instrument. Each strip-like tooth has the upper part of its side edges tapered to a point at the top, and a periodically operated depressor bar for the meter needle is provided, so that at regular intervals the bar forces the needle against the serrated structure constituted by the row of teeth, 1. e.

moving the latter down to a position crossing the edge of a tooth. The controlled electrical circuits are such that the needle is intended to come to rest in the V-shaped depression formed by the slanting edges of two adjacent teeth, and thus to make electrical contact with both of the latter. Under such control the electrical transmitting circuits are appropriate to provide an indication, for instance at some remote station, of the instantaneous position of the galvanometer needle.

A particular difliculty experienced with these devices is that the needle often fails to move into the valley, so to speak, between adjacent contact points. Even though the latter may not have worn dull, it has been found that if the depressor bar happens to move the instrument needle directly against the point of a tooth, the final force of the stroke merely causes the needle to hang, in effect, on the contact point without moving down on one side or the other so as to make contact with an adjacent element too. In passing, it may be noted that ordinarily devices of this sort are designed to transmit only a reasonable approximation of the position of the movable member, so that if the latter happens to stop just above the point of a contact element, it is relatively immaterial on which side of the element it falls, or should fall, when struck by the depressor bar. On either side the transmitted reading is sufficiently close to the actual one for the desired purpose of remote indication, control or the like, but it is essential to have the needle move down on one side or the other and make the described double contact.

Instead of a galvanometer the instrument actuating the movable member can be any of a variety of other instruments, such as a barometer, altimeter or the like; transmitters of this general type are of particular utility where the pointer is very free-moving and could not, of itself, exert suflicient force to operate contacts or even sweep across a row of contact elements.

An important object of the present invention is to provide improved and more reliable transmitting means and systems of the character described, a particular object being the provision of a novel switching arrangement of the depressor actuated type wherein assurance is afforded that the selecting member will be moved into the desired condition of contact in a place corresponding with reasonable accuracy to the position selected for such member by its controlling meter or other instrumentality. Further objects are to provide rugged, relatively simple and yet adequately sensitive switching means of the character stated, embodying one or more novel structural features or combinations.

To these and such other ends as may be hereinafter apparent or incidental to the use of the apparatus disclosed, a presently desirable form of the invention is shown in the drawings and hereinbelow described, by way of example to illustrate the novel principles and features of structure that are involved.

Referring to the drawings:

Figure 1 is a perspective view, fragmentary in parts and somewhat diagrammatic, of a sensitive instrument embodying transmitter means of the present invention.

Fig. 2 is an enlarged fragmentary plan view of switching instrumentalities shown in Fig. 1.

Fig. 3 is in effect a section on line 3-3 of Fig. 2, except that for clarity of illustration the contact structure is shown as if arranged along a linear rather than a curved path.

Fig. 4 is an elevation, as from the left hand side of Fig. 3, but with a portion shown as if in central section on a plane parallel to the plane of elevation.

Figs. 5 and 6 are enlarged perspective views of the contact-making elements in respectively different positions; and

Fig. 7 is a wiring diagram constituting an ex- 3 ample of one arrangement of connections that can be embodied in the transmitter system.

Fig. 8 is a fragmentary view similar to Fig. 4 showing certain insulation used with the circuit of Fig. 7.

Referring to Figs. 1 to 4, inclusive, the improvements are shown as if incorporated with a sensitive instrument ll? of the galvanometer type having core structure ll, 12 and a movable coil l4 mounted to swing a member 15 about a vertical axis in accordance with the energizati-on of the coil by appropriate means not shown. It will be understood that an instrument of this type may be employed for a wide variety of pur-- poses, for instance in automatic weather stations where photoelectric or other meteorologically sensitive devices may be employed to energize the coil H1 in accordance with observed conditions. In such circumstances it is desirable to provide a continuous indication or record at some-remote locality of the readings of the instrument, and the transmitter structure now to be described may be employed for such purpose. As stated above, any of a variety of other instruments may be substitutedfor the galvanometer H), and likewise-use of suchinstrumentsand' of the'con-trolled transmitting system may bemade in a wide variety of circumstances other than for weather indicating purposes; 1. e. in any situation Where remote-readings areto be had of a sensitive device.

Along the curved path followed by the member it there is disposed a' contact structure comprising a supporting base I]; conveniently made of insulating material such as hard rubber, Bakelite, polyvinyl chloride or other plastic. The base ll has an upstanding wall portion 53 and an upper surface comprising annular projections 59, 2!! which extend vertically'and bound a relatively Wide annular depression 24-, the portions 19, 2E! and 2!. following the curve of the member ll throughout its length. Each of the upstanding flanges i9, 20 is provided with a multiplicity of transverse grooves 25, to seat the ends of a multiplicity of contact bar-sthat extend across the recessed portionZl. In the example shown, the contact bars are formed .of wire of appropriate conducting metal and constitute elemente 25, 2.6 alternately-extending ever the inner and outer faces of the supporting member H; That is to say, every other contact bar is designated. 25 and constitutes a portion of Wire that has its outer end seated a. groove in the rib i9, thence traversing the space 2.] and a corresponding groove in. the rib 2.9,. and. having a further portion 27 which is bent down over the insideface of the member l]. Alternating with the bars 215 are the bars 26, .eachcomprising. a length of wire having its outer end seated in the inner rib 2G, crossing thespacell and traversing a groove in the outer rib l9, with a nor-- tion 28 bent over to extend down along'the er surface of the member H.

Thus the successivewire portions '25, 2 35s aced throughout the curved length of the base 11,. provide an array or series of contact bars extending transversely of the path of the movable member 5. In alternation, the wires extend of ten each, and connecting the wires on the other side of the member in a distributed multiple arrangement so that, say, every tenth wire can be connected to a given one (in order) of a series of ten circuits, the successive circuit connections of the last mentioned wires being duplicated for each set of ten wires corresponding toone of the first mentioned groups. Thus by way of example, the inner face of the supporting wall I8 carries a serles of connector elements 39 arranged in spaced end to end relation and having projecting shelf portions M with appropriate holes in which the downwardly turned wire portions 2? may be in serted and soldered for electrical contact as shown. Secured in spaced relation to the outer face of the wall 58, a plurality of insulating panels 33 are provided, having a conforming curvature as shown in Figs. 1 and 2 and arranged in end to end relation around the device. of the wires 28 extends down along the outer face of the wall 18 and through a corresponding aperture in the adjacent member 33, so as to provide an outwardly projecting stud Assuming, for instance, that the outside connections areto'be made in multiples of-every tenth wire, the lengths of the wire portions 28 and the localities of the apertures in the panel 33 may be so related that the studs 3 occupy a series of positions that are spaced in succession, both vertically and horizontally. Thus in the device shown the projecting studs are arranged in-a row extending diag onally of the panel face, so that connecting bus wires (itcanbe disposed circumierentially around the apparatus, each of them being connected to a corresponding stud of every panel.

It willnow be seen that if the inner group-connectors 3i represent successive increments of units each along a decimal scale for the pointer I5, the outwardly'connected wires can represent unit values in each of the inner groups, and the several circumferential connectors 35 may there-- fore be taken to represent such unit values or successive increments of one (inorder from zero to 9), for each of the inner or tens groups.

in accordance with a greatly preferred. feature of the present invention, the contact bars 25 2-6, instead of traversing the space 21 in a perpendicular direction, i. e., in a direction extending radially of the circular are through which the member i5 swings, are arranged at an acuatc angle to the corresponding radii. Thus, as clearly apparent in Figs. 1' and 2, the wires are approximately parallel (actually here, at a small angle) to each other, but are all disposed at a predetermined acute angle to the-circular path or, by the same token, at a predetermined acute angle to the radius of such path.

For contact at desired times with the 2% 2-6, theouter end of the member I carriesa strip portion fill of thin, flexible, resilient metal such as Phosphor bronze, or. beryllium. copper, having aportion 4 I. turned downwardlyzat an angle-,pret- 'erably an acute angle, to the'plane of thebars 25, and terminating .ina contactgportion comprising a V-shaped. edge 42. as shown. Thus by "reason. of the flexible resilience of the member All, the contact portion :42 is. mountedfor at least limited movement ina direction across the path of the member l5. Normally the latter is disposed so that the contact part is clear of the wires 25, 26, as will be seen most clearly in the solid line position of Figs. 3, 4 and 5. Although various means may be provided, including in some instances manually operated means, for periodically engaging the contact portion with the-array of contact bars, an automatic depressor bar is usually preferable and one form of such construc tion is shown in the drawings by way of example. The depressor comprises a, curved bar 5!} having a contour conforming with the are through which the member l5 travels, the bar 59 having a supporting portion 5| in the form of a transverse shaft carried by suitable bearings 52.

Various means may be employed for periodically rocking the bar about the axis of the shaft 5|. For example the latter may carry a projecting arm 54 resting, as a follower, on the surface of a cam 55 having an appropriate high spot 55. The follower 54 is urged against the surface of the cam by the tension of a spring 5?, and the shape and size of the cam are such that the spring thus normally holds the bar 55 in a position vertically clear of the upper surface of the member l5. The cam 55 may be rotated by suitable means, such as a motor 58, so that the cam rise 55 periodically rocks the arm 54 and consequently rocks the curved depressor bar 55 downwardly about its supporting bearings 52. When so moved, the bar engages the upper surface of the member l5, conveniently onthe portion 39, and pushes the contact edge portion =22 down against the array of contact bars. It will be understood that the member !5 includes suitable resilient flexibility, for example at a portion 69 thereof or elsewhere within its length or at its mounting so that it can be moved down easily by the depressor bar. Until the edge part 42 strikes the contact bars, the downward motion (in its first part) can thus be effected without bending the strip arrangement 49-42. The final part of the downward stroke of the depressor bar flexes the strip 4U4l and causes the contact edge 42 to slide into the desired position between two contact wires, in a manner more fully explained hereinbelow.

As stated, the device shown is intended to provide simultaneous contact of the portion 42 with a pair of adjacent contact bars corresponding as closely as possible to the position given the member l5 by its actuating means I8. It will now be appreciated that any of a wide variety of transmitting circuits and remote indicating, recording or control means may be operated by the described switching device, such circuits including, if desired, electrical connection to and through the element 45, for example by means of the depressor bar 55 which necessarily makes contact with the element throughout each interval in which the bar forces the edge portion 42 into engagement with the contact wires. Merely to illustrate one even simpler scheme of connection, Fig. 7 shows a transmitter-system including a rudimentary type of indicating means for representing the position of the member i5 by appropriate numbered elements.

the several magnets 62 by one of the conductors 56. There are ten for vair from zero to 9 inclusive, and by the conductors 6'! one terminal of each magnet 83 is connected to a corresponding one of the bus bars 35 which represent unit-position sets of the contact wires 26.

Thus for instance there may be a plurality of tens order solenoids The other terminals of the magnets 62 are all connected together to a common conductor 68, and likewise the other terminals of the magnets 63 to a common conductor 69, and the circuit is completed with a source of current such as the battery connected between the two conductors last mentioned. Simultaneous energization can thus be had of any selected one of the magnets 52 and any selected one of the magnets 63, in series across current source 10, upon making connection between the appropriately corresponding contact bars 25 and 26. Alternatively if desired, parallel energization circuits can be provided for the magnets or like devices by using a common return path (not shown) for the wires 68, 69 through a battery to the element 4!].

It will now be seen that when the contact portion 42 engages any two adjacent bars 25, 25 a circuit is completed through one each of the magnets 62 and 53, energizing both and attracting their respective armatures. Since no other magnet can be energized, the combination of in dicia displayed by the two attracted armatures registers the position of the pointer 15, by a twoplace number. The contact groups 31 represent successive increments of ten units each from the end of the scale (here shown at H although other terminal points can be used) and the bars 26 represent increments of one unit in each and any of'the tens groups so that the remotely displayed number has appropriate figures in the tens position (magnets 62) and the units position (magnets 63). Thus if the contact element fi-42 stops and is depressed between two bars 25, 25 at the scale point shown for example in Fig. 7, the attracted armatures correctly state its position as 28 units from the end of the scale. Of course, further tens groups (up to 9 or even more) can be provided beyond the few shown in Fig. 7, and alternatively the contact bars can be connected in other groupings and arrangements, e. g. to read values of angles, time or the like measured in non-decimal notation.

With the specific circuit of Fig. 7 a false reading will occur if the contact element =5-42 happens to be depresse between the last right-hand bar 25 of any group 31 of such bars and the immediately adjacent bar 25 that corresponds to the figure zero (0). To avoid such result, the small space between these specific bars, i. e. at the extreme right end of each group 35 (Fig. 2) may be filled with insulating material 772 built up to a slightly convexity between the bars as shown in Fig. 8 so that if the point 42 of the member 453 should initially strike such material, it will slide off (in the same manner as hereinbelow explained) to make contact with the pair of bars on one side or the other.

Referring again to Figs. 2 to 6, inclusive, the operation of the instrument should now be relatively clear from what has already been said. The movement it positions the member i5 according to the desired controlling condition. and each time the depressor bar 5?! is actuated the contact portion 42 is brought into engagement with a pair of contact bars to complete the desired elec trical transmitting circuits. In particular, the arrangement is adapted to provide a positive and entirely reliable contact operation whenever the depressor bar is actuated. insuring hat the contact portion actually engages two adjacent bars and does not stick or hang on a single bar.

It will be noted that upon depressor actuation the contact portion 52 not only moves downward but in the later stages of the depressor bar moveament s i ewee amiin t planed theaq n a ars y,r I onof 'ts.resilientlyqfiexibleconstruc- V on. 1- In {the device showm-ait is thus displaced out-'vyardly oi the path-of the membervl 5,-and by syirtue of the later-a1 'freedomof. movement of the ember, either because the metermechanism I8 prmits at least -a .small.,angular displacement aboutthe axis of swinger becauseg-the-member i 5 may itse be sufiiciently re s ilient to .allow a slight lateral deflection, the contact-portion-then aver ,readily-tendslto slide tram the top of a bar 2 5 -or ;2B intothe groovebetween such .bar and oneinext to it. Whereas a mere downwardrnovement of the contact portion might simply jam its end howeverpointed or otherwise convex, against the very top of a contactwire, the transversedis- .placementof; the contact element tends to disturb therelatively unstable equilibrium of such a-conditio n and to causethe end of'the elementtoiall .,or slide downaside of thewire into the desiredexplained above the bars are all disposed at the same, selected acute angle to the radii of thepath. The angle may be one of various values, depending ,oncircumstances and on convenience of mounting of the bars; for instance 15 to '20 degrees has .been found satisfactory ,for the device shown. This disposition, ofthe contact wires materially promotes the desired -movement of the contact -por-.tion,42 into the desiredposition intermediate ,a pair of such members; as clearly shown in Figs. 2A, the displacement afforded by the downward-bending or flattening of the member Mlinto the dot-and-dash line position is ordinarily radial and thus automatically tends to have a component anangle to the axes of the angularly disposed contact bars. The efifect of this component of motion is to slide the point of the outwardly moving contact portionlofi the top of a bar upon which :it may have been initially poised, so that in the z-finalstage of the downward and outward push exerted by the depressor bar and with the aid of slight lateral movement of the member l5 if necessary, the V-shaped contact edge drops into proper position between two .wires 25, 26 and in firm contact with both under the pressure of .the bar 58.

'In consequence of the described relationships, each operation of the depressor necessarily forces theend :of the element. into double-contact position between a pair of the contact bars, even though theelement may initially hit the top of .a bar. 'Inmany cases the motion will be as shown in Fig. 2, taking advantage of the angulur bar position, but sometimes when the point of the element 48 strikes on or near the top of a bar, conditions are such as to cause it to slide in the other-direction and thus come to rest inabutment with the next bar on-the other side. As explained, either position represents a reasonably accurate reading of the instrument, for actuation of appropriate indicating or control-means.

It is to be understood that the invention is not limited to the specific structures herein shown ,or described but may be embodied in other forms without departure from its spirit.

I claim:

1. -Electrical transmitter means comprising, in combination, a member adapted to he positioned at any place along a predeterminedpath, an array of regularly spaced contact bars alongthe-path,

pthe latterto move-transversely of thegpath rtoi-nsure its being seated between barsmshenthesaid end .is urged against the bars by the --.depressor -means.

, 2. .Electrical transmitter. means.accmprising-gin combination a meter element movable ,-along..::a predeterminedepath, an array of contact =bars spaced side byside along said path, saidelement having a contactportion shaped to fit between :and -incon tact-with a pair of bars upon abutment of said portionagainst said array :of ..bars,-;,a-nd means for pressing ,said elementintoqabutmfint of saidcontact portion with. theearray. of; sai ;-c0 1 a po ti n b in 'y eldab v upper e {or-movement thereof in ,a, directiomtansvegse of the path-when urged into sa-id -:abu tment,.;;iby I said pressing means andeach oftsaidbars being disposedat an acute angle to -said lastmentioned direction; to promote dispositionuof the contact .,."portionin engagement between and ,inycentact vwith apair of the bars.

-Electrical;transmitter means com-prising dn combination, a member ;mova*ble along; a predeterminectpath, a, series of I space n'tact -:ha;rs each extending 1 transversely of e 1132/1111, n-sagid series:extending-along said path andrcomprising a multiplici-ty of said fibers each sfi stan ially parallel to the -ethers, saidmernher includlnen contact portion shaped to engage the barsgrin .electrical contact with ..a=. pair. ofgthemwseleuted from ;.mu1tip ci y -;cf-such:pai s:rinzaccordanc with the position-otthe.,meinber; and said:.member beingnormally adisposedwith qsaid --contact portion clear of the bars,; and edepressor means for.-movinggthe memherto press the;contact:i1orltion against the :floars, said embergin-cl: ding yieldable supporting; structure; or; effecting slidingmovement of said contact port-ion: upon :apbar and at an acute/angle thereto,:=under pres site of said depressor means, to promoteathe waforesaid engagement of saidportion'incontactnwith .a pair of the bars.

- 4. Electrical transmitter'mca-ns comprisinggin combination, amember-movablegal-ong a predetermined path, a series of contact bars transverse ofthe path an acute; angle;.thereto,.=:aid member including --a -port-ion -;-shap,ed torengage said series in: electrical -contact With latmair :of said bars,- said, member being normally ndisposed for clearance between said-:portiongandcsaidbars as themember moves along t-he;-path,;and intermittently operable leans f-or moving :fthe member against {the -series. of years, ;.said -member including structure mountingzthes aidportion for m ovement rel ativeto; the ;ab ars, transverse: of :the path and at an angle different from the aforesaid acute angle, said intermittently -operable means being adapted, on pressing the member against the series of bars, toefiect thelast-mentioned movement of the member, for promoting electrical contact ofthe aforesaidportion .ofzthe member with a pair of; the bars.

5. In -a n electricalswitching device, incomb-ination-a membenmova'ble: along a .prede.term-ined path, and a series of contact bars spaced along said path each at a predetermined acute angle thereto, said member including a resiliently flexible part and a contact portion shaped to fit between and in electrical contact with any pair of said bars, said member being adapted to be urged toward said series of bars to press said contact portion against the latter, and said flexible part being adapted to bend when the contact portion is pressed against a bar, to eifect sliding movement of said portion perpendicularly across the path and thereby to promote seating of said portion between and in contact with a pair of the bars.

6. Electrical transmitter means comprising, in combination, a member movable along a predetermined path, a series of spaced contact bars each extending transversely of the path, said member including a contact portion shaped to engage the bars in electrical contact with a pair of them and said member being movable relative to the path so as to be disposed for clearance between said portion and said bars as the member moves along the path, and depressor means for moving the member toward the bars to press the contact portion against the latter, said contact portion being yieldably supported for some sliding movement transverse of the path when pressed against a bar by the depressor means and said contact portion and bars having mutually engageable faces of convex configuration to promote displacement of the contact portion into position of contact with a pair of adjacent bars upon the aforesaid sliding movement of the contact portion.

7. Electrical transmitter means comprising, in

combination, a movable member, an instrument for positioning said member along a predetermined path, said instrument normally exerting insumcient force on said member to move it against any substantial retarding pressure on the member, a series of spaced contact bars each extending transversely of the path at a predetermined angle thereto, said member including a contact portion adapted to fit between and in electrical contact with any pair of the bars, and said member being normally disposed for clearance between said portion and said bars as the member moves along the path, and depressor means for moving the member toward the bars to press the contact portion against the latter, said contact portion and bars having mutually engageable faces of convex configuration to facilitate the aforesaid relation of contact, and said contact portion being yieldably supported for sliding movement upon an adjacent bar at an acute angle thereto, when pressed against said bar by the depressor means, to promote disposition of said contact portion in the aforesaid contact relation.

8. Electrical transmitter means comprising, in combination, a movable member, an instrument sensitive to small actuating energy for position- Number ing said member along a predetermined path, said member being mounted in said instrument for at least some freedom of movement along the path in response to application of substantial external force to the member, a series of spaced, round contact bars each extending transversely of the path at an acute angle thereto, said member including a resiliently flexible strip having a sharply convex end edge and extending obliquely toward said series of bars with its side edges aligned in the path, and said member being normally disposed with said end edge clear of the bars, and depressor means for moving the member toward the bars to press the end edge of the strip between and in electrical contact with the nearest pair of bars, said end edge being adapted for sliding movement on the surface of a bar under pressure of said depressor means, perpendicularly across the path by the flexibility of the strip and lengthwise of the path by the aforesaid freedom of movement of the member, to promote seating said end edge between a pair of bars.

9. In an electrical switching device, in combination, selecting contact means movable along a predetermined path, selectable spaced multiple contact means including a surface providing a predetermined arrangement of elevations and depressions alternating along said path, said first and second mentioned means being normally separated but capable of mutual abutment, an intermittently operable device mechanically associable with at least one of said means for pressing one toward the other into said mutual abutment, said first mentioned contact means having a contact-making surface shaped for fitting relation in any one of said depressions in engagement with sides of the elevations adjacent thereto, and one of said contact means being yieldably supported and biased for sliding motion under the abutment-effectuating pressure of the aforesaid device, across the surface of the other cont-act means in a direction effecting relative displacement of the aforesaid contact-making surface and the path-lengthwise alternation of elevations and depressions in said arrangement, whereby said sliding motion of one contact means cooperates with the arrangement of elevations and depressions to bias the aforesaid contact-making surface to be seated in one of the depressions.

JOHN O. KIRWAN.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date 322,701 Italy Nov. 21, 1934- 324,143 Italy Jan. 22, 1935 

